1. Field of the Invention
This invention relates to clutch and torque multiplier devices and more particularly to a centrifugally operated clutch and variable ratio torque multiplier.
2. Description of the Prior Art
At the present time, there are many known clutches and torque multipliers which are employed primarily as transmission devices for vehicular driving purposes, and some of these devices employ steel balls which are moved radially to vary the ratio between the driving and driven elements of the device. In general, devices of this type employ mechanical mechanisms to move the balls radially, and these devices are therefore relatively complex and can cause considerable maintenance and repair problems.
To the best of my knowledge, only one clutch and variable ratio torque multiplier device has been devised which employs steel balls that are moved radially under the influence of centrifugal force to vary the ratio between the driving member and the driven member. This device, which is fully disclosed in U.S. Pat. No. 3,762,519, issued on Oct. 2, 1973 to the same inventor, comprises a drive member that includes a ball carrying disc which is axially movable on and is rotatably driven by the input shaft, and a driven member which includes a housing having a power takeoff device thereon, with the housing coaxially journaled for rotation about the input shaft. The housing has an inner chamber which is conical at one end and which is joined at its wider end by a cylindrical surface. A plurality of axially staggered recesses are formed in the cylindrical surface immediately adjacent the conical surface. The ball carrying disc is spring loaded toward the conical surface and the balls roll freely thereon at idle speeds of the input shaft which results in zero rotational driving of the housing. As the input shaft speed is increased, centrifugal force moves the balls radially which increases frictional engagement between the balls and the conical surface, thus resulting in rotational driving of the housing. This same increase in RPM of the input shaft will cause the disc to move away from the conical surface due to interaction of the balls and the conical surface. Thus, at intermediate and higher speeds of the input shaft, the balls will leave the conical surface and enter onto the cylindrical surface where they engage the recesses with hammer-like impacts. At the end of the cylindrical surface which is remote from the conical surface, a disc clutch is provided which effectively locks the driving ball carrying disc member to the driven housing at high speed to eliminate slippage therebetween.
This particular prior art clutch and torque multiplier has proven to be a very reliable and virtually trouble free device and has only one drawback, which is that at intermediate input shaft RPM, i.e., between the speed at which the balls move onto the cylindrical surface and maximum speeds where the disc clutch locks the drive and driven members together, the device produces a relatively loud clicking or chattering noise. This clicking or chattering noise which results from the hammer-like impacting of the balls with the axial recesses, is annoying and irritating to some people, and has caused some people to express conern over the proper operation of the device.
Therefore, it is desirable to provide a new and improved centrifugally operated clutch and variable ratio torque multiplier which overcomes some of the drawbacks of the prior art.